1. Field of the Invention
This invention relates to a catalyst for the hydrogenation of carbon monoxide or carbon dioxide to be used in synthesizing methanol and/or hydrocarbons by the reaction of carbon monoxide or carbon dioxide with hydrogen and to a method for the synthesis of methanol and/or hydrocarbons by hydrogenation using the catalyst.
2. Prior Art Statement
Being easy to transport and useful .in various applications, methanol has become a basic substance in the chemical industry. Commercially, it is synthesized by the reaction of carbon monoxide (CO) with hydrogen. As a catalyst for this reaction, wide use is made of the catalyst (Cu/ZnO) produced by immobilizing copper (Cu) as an active metal on zinc oxide (ZnO). In the actual commercial process for the production of methanol, a Cu/ZnO/Al.sub.2 O.sub.3 catalyst or a Cu/ZnO/Cr.sub.2 O.sub.3 catalyst, each incorporating a third component, is additionally used. Though these catalysts exhibit high activity and excel in selectivity, they require reaction temperatures falling in the range between 200.degree. C. and 300.degree. C. under reaction pressures in the range between 50 and 100 atmospheres (5.times.10.sup.6 and 1.times.10.sup.7 Pa).
In recent years, the reaction for synthesizing methanol as a useful substance by the combination of carbon dioxide with hydrogen has become the subject intensive laboratory research aimed at enabling effective utilization of carbon dioxide, one of the substances responsible for global warming. Virtually all the catalysts used for the reaction have been those of the Cu/ZnO type. The required reaction conditions include pressures in the range between 50 and 100 atmospheres (5.times.10.sup.6 and 1.times.10.sup.7 Pa) and reaction temperatures in the range between 150.degree. C. and 250.degree. C.
It is a characteristic of these reactions for synthesizing methanol by the hydrogenation of carbon monoxide or carbon dioxide that the equilibrium conversion increases with decreasing reaction temperature. In other words, the maximum amount of methanol theoretically obtainable from a given amount of raw materials increases with decreasing reaction temperature. Thus, a strong need has been felt for the development of a catalyst exhibiting high reactivity at the lowest possible temperature.